# Council Regulation (EC) No 21/2004 of 17 December 2003 establishing a system for the identification and registration of ovine and caprine animals and amending Regulation (EC) No 1782/2003 and Directives 92/102/EEC and 64/432/EEC, Division 2: The means of identification must display a code providing the following information in the indicated order:

Extent: E+W+S+N.I.

(a)either the two-letter alpha code or the three-digit numeric code(1), based on ISO 3166, for the United Kingdom or for the Member State in which the holding where the animal was first identified is situated (country code);
(b)an individual animal code of no more than 12 digits.
In addition to the codes referred to in points (a) and (b), and provided that the legibility of those codes is not affected, the competent authority may authorise a bar code and the addition of supplementary information by the keeper.

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Source: https://www.legislation.gov.uk/eur/2004/21/annex/division/A/division/2 (the official version)
Page: https://openlegislation.uk/eu-regulation-2004-21/annex/division-A/division-2
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.